The project aims at the development of novel ultrafast laser processing schemes for the 3-dimensional biomimetic modification at micro- and nano- scales of a variety of substrates, including biopolymers.

Nature inspires us in tailoring the surface energy of materials based on synergetic effects between chemical composition and surface morphology. We have developed an efficient method to achieve controlled dual scale rough surfaces by femtosecond laser structuring of planar silicon wafers. It is possible, by varying the laser pulse fluence on the surface, to achieve a systematic and reproducible variation of roughness at micro- and nano-length scales which mimics the hierarchical morphology as well as the wetting response of natural water repellent surfaces. The superhydrophobic and self-cleaning properties of the high roughness ratio artificial surfaces were compared to that of the Lotus (Nelumbo Nucifera) leaf, one of the most water repellent surfaces found in nature, and remarkable similarities were observed. Alternatively, the different structures obtained by this method can be advantageously transferred to a variety of polymerics substrates, including biopolymers, through replication molding techniques. Further control over wettability can be achieved by altering the surface chemistry by coating the structures with various conformal layers, while keeping the same morphology. As a consequence, it is possible to preferentially tune the wettability of the artificial substrates from superhydrophobic to superhydrophilic through a proper combination of surface topography and chemistry.